Wikipedia has strict rules for photography and copyright, so the pictures uploaded must be a contributor's own, freely licensed or in the public domain.
As a result it contains many images added by enthusiasts rather than taken by photographers.
In some cases that merely means a non-descript image - but sometimes they are much worse than that.
A prime example: the comedian Emil Wakim, of Saturday Night Live fame.
For a week last November, the photo above - apparently taken at a stand-up show in New York - was his Wikipedia picture.
When it was removed, an editor noted "having no picture is better than what's currently there".
The photo of the English footballer Kyle Bartley, taken in 2011, has also been highlighted by social media users as evidence of Wikipedia's picture problem.